Wax refining



May 3, 1966 F. J. STARK, JR., ET AL WAX REFINING Filed Feb. e. 1961United States Patent 3,249,525 WAX REFINING Fred J. Stark, Jr.,Kirkwood, and Robert M. Thompson,

Clayton, Mo., assignors to Petrolite Corporation, Wilmington, Del., acorporation of Delaware Filed Feb. 9, 1961, Ser. No. 88,216 6 Claims.(Cl. 208-27) This invention relates to an improved process for refininghydrocarbon waxes. More particularly, this invention relates to animproved wax refining process whereby petroleum wax is improved by theremoval of, or by the reduction in, color and color-forming bodies,aromatic content, sulfur, nitrogen, combined oxygen, trace metals andother undesirable materials present in the wax. This invention alsorelates to the products produced by the process, and particularly to ahydrocarbon wax characterized by substantial freedom from aromaticity.

In refining hydrocarbon waxes, such as those derived from petroleum, itis necessary to purify the product so as to remove color and otherundesirable impurities. It is generally difficult to produce white waxsince complete removal of color bodies from wax is quite diflicult. Invaddition, it is desirable to remove certain undesirable materials whichexist in trace quantities.

Recently there have been additional standards imposed on waxes whichcome in contact with food whereby restrictions have been placed on thepresence in waxes of certain compounds containing aromatic condensedring systems, i.e. compounds where one aromatic ring is fused to atleast one other aromatic ring so as to retain general aromaticity, suchas in anthracene, phenanthrene, pyrene,

benzanthracene, dibenzanthracene, benzpyrene, etc.

We have now discovered a process for refining hydrocarbon waxes wherebysuch waxes are improved by the removal of, or by the reduction in,colorl and color-forming bodies, aromatic content, sulfur, nitrogen,combined oxygen, trace metal content and other undesirable materialspresent in wax. Our process is particularly effective in removing orreducing the presence of compounds containing aromatic condensed ringsystems, also referred to herein as condensed ring aromaticity.

The waxes refined according to this invention are hydrocarbon waxes,such as petroleum waxes. These include (1) tank bottom derivedmicrocrystalline wax; (2) residual lube stock derived microcrystallinewax; (3) intermediate lube stock derived wax; and (4) paraffin Wax.

The figure of the hereinafter cited Bruce Clary article presents anexcellent schematic outline for preparing these waxes. The waxesthemselves, or products intermediate in the preparation of these waxes,can be treated in themanner of this invention. For convenience, a numberhas been assigned to designate each wax type and intermediate formedduring the processes. The number indicates the product formed uponcompletion of the indicated process step in the general line of priorprocess steps. For example, 8 (first vertical column of blocks, blockDeoiling) is the product formed after the deoiling of deasphalted,distillation residue from dehydrated crude tank bottoms; 15 (secondvertical column of blocks, block Deoiling) is the product formed afterthe deoiling of deasphalted, dewaxed residual lube stocks. Certainnon-limiting wax intermediates presented in Table I, will be employed inthe examples to illustrate the inven. tion.

rice

Patented May 3, 1966 TABLE. I

Wax No. (Fig. 1)

Type of Wax 14 (block Petroletum," second vertical column of blocks).

15 (block Deoiling, second vertical column of blocks).

20 (block Crude Intermediate Wax, third vertical column of blocks).

21 (block Deoiling, third vertical column of blocks).

27 (block Solvent Deoiling,

fourth vertical column of blocks).

Crude Tank Bottom derived microcrystalline wax subsequent to deoling.

Petrolatum.

Crude Residual microcrystalline wax after deoiling.

Crude Intermediate wax prior to deoiliug.

Crude Intermediate wax subsequent to deoiling.

Crude Scale wax subsequent to solvent deoiling.

tank bottom, microcrystalline, residual microcrystalline,

intermediate wax and refined paraffin, for example, in place ofcontacting the wax with an absorbent material such as bauxite, clay,alumina, silica gel, charcoal and the like.

Petroleum waxes and the processes by which they are manufactured are toowell known to require further elaboration. In this regard note thefollowing publications:

(1) How to Iudge, Use and Handle Microcrystalline Waxes by Bruce Clary,Paper, Film & Foil Converter, September and October, 1955.

(2) The Chemistry and Technology of Waxes by Warth, published byReinhold, 2d edition (1956).

(3) Decolorization of Petroleum Waxes by Absorbent Percolation by WillisA. Johnston, Petroleum Processing, pages 2-8, September 1947.

(4) Commercial Waxes, by H. Bennet, Chemical Publishing, 2d edition(1956).

An excellent schematic presentation ofthe steps employed in themanufacture of petroleum wax can be found in FIG. 1 of the Bruce Claryarticle (1), which is referred to here in column 1, and particularly inTable I above.

Our refining processes are outlined schematically in the figure.

A procesa- The wax to be refined I is treated with an alkali metal (withor without ether) to yield wax and precipitate II. This product is thentreated with CO2 and the precipitate removed to yield wax AI. Wax AI canbe further refined by hydrogenation, followed by precipitate removal, toyield refined wax All.

B procesa-The wax to be retined I is treated with an alkali metal (withor without ether) to yield wax and precipitate II. This product is thentreated with oxygen and the precipitate removed to yield wax BI. Wax BIcan be further refined by hydrogenation, followed by precipitate removalto yield refined wax BII.

C processes.--The wax to be refined I is treated with alkali metal (withor without ether) to yield wax and precipitate II. The precipitate isthen removed to yield wax filtrate Ill which (if it tests positively forcondensed ring aromaticity) is then treated with alkali metal,preferably with ether, at point H, then treated with CO2, followed byprecipitate removal, to yield wax CI. Wax CI can be further refined byhydrogenation, followed by precipitate removal to yield refined wax CII.

D procesan- The wax #to be refined I is treated. with alkali metal (withor without ether) to yield wax and fp d precipitate II. The precipitateis then removed to form wax liltrate III which (if it tests positivelyfor condensed ring aromaticity) is then treated with alkali metal,preferably with ether, at point I, followed by ltreatmentwith O2 andprecipitate removal -to yield Wax DI. Wax DI can -be further refined byhydrogenation followed by precipitate removal to yield refined wax DII.

E process-The wax to be refined I is treated With alkali metal (with orwithout ether) to yield wax and precipitate II and the precipitateremoved to yield Wax filtrate III which is then hydrogenated, followedby precipitate removal, to yield rened wax EI. If hydrogenaltion iscarried out with an active hydrogen compound (instead of hydrogen),alkali metal, preferably with ether, is added at point J.

F prcess.-The wax to be refined I is treated with alkali metal (withorwithout ether) to yield wax and precipitate II which is -thenhydrogenated and the precipitate removed to yield refined wax (FI).Since the presence of the precipitate tends to shorten` the life of thehydrogenation catalyst, this hydrogenation is carried out with an actvehydrogen compound rather than with hydrogen.

Although alkali metals alone, wi-th or without ether, or these alkalimetal treated products further treated with CO2 or O2, with or withoutether, produce refined waxes, .these waxes can be further refinedaccording to these processes in combination with hydrogenation.

`In the above processes subsequent to .reaction with alkali metalemploying ether, ether is removed by any suitable means, for example, bydistillation prior to removal of the precipitate. This reduces lthesolubility of the precipitate in the wax.

The product of any sequence of steps can be rerun according to the verysame process employing all of the same sequence of steps, or less thanthe full sequence of steps; or the product of any sequence of steps canbe rerun according to another sequence of steps, or less than the fullsequence of steps, of any process outlined in the figure. For example,the product AII can be rerun according to the same process which hasproduced AII,

or the product of All can be rerun by the A process up to AI, or theproduct BII can be rerun according to the C process, or product CII canbe rerun according to D process, etc.

It is noted in the figure that the wax to be rened can be treated withalkali metal with or without ether at point G. Although both methods canbe employed, in the preaferred embodiment we first treat with an alkalimetal in the absence of ether. This procedure tends to yield a lighterwax having a lower sulf-ur content than is produced by treatment withalkali metal in the presence of ether. On the other hand, the use ofalkali metal in the presence of ether facilitates the 'alkali metalreaction. l

Therefore, it is preferable that the initial alkali metal treatment becarried out without ether and the wax and precipitate II thus obtained-be filtered to yield wax ltrate III. Wax filtrate III can be-hydrogenated with hydrogen to yield refined wax EI. lined as follows:

Preferred E process- Alkali metal Wax t0 be rened I Y (without ether)Prccipitate Wax and Precipitate II Removed Hydrogen then Wax FiltrateIII Refined Wax EI This preferred procedure is o-ut- In general, thechief reason for hydrogenating, oxygenating and carbonating is to removeor reduce condensed ring aromaticity still present in the wax afteralkali metal treatment. Therefore, after filtration of the alkalimetal-treated wax it is advisable to examine the wax filtrate forcondensed ring aromaticity. If the wax filtrate tests positively forcondensed ring aromaticity, one adds additional alkali metal, preferablywith ether, at points H, I and l, and then proceeds to carbonate -by Cprocess,or oxygenate by D process, or treat with an active hydrogencompound by E process. It should be noted that this alkali metaladdition is made only if hydrogenation is carried out employing acompound containing an active hydrogen. Additional alkali metal is notrequired if hydrogenation is carried yout with hydrogen (H2).

It is to be noted that the most effective agent in removing condensedring aromaticity in waxes by alkali metal treatment is thesodium-potassium alloy, for example the 50:50 Na:K alloy.

In the case of F process involving Wax and precipitate II it isdesirable that hydrogena-tion be carried out with a compound containingan active hydrogen rather than with hydrogen (H2) since the presence ofthe precipitate tends to shorten the life of the hydrogenation catalyst.

ALKALI METAL TREATMENT In general, the process is carried out bytreating the -hydrocarbon wax with an alkali metal, for example Li, Na,K, Ru, etc., and alloys thereof. For convenience and intimacy ofcontact, this treatment is carried out while the wax is in a liquidstate. by heat, solution or a combination'of both. Since the process issensitive to many solvents, when it is desirable to employ a solvent, itshould be a non-reactive liquid -hydrocarbon in which the wax issoluble. Because of the reactive nature of alkali metals it is lhighlydesirable to carry out this reaction in a dry, inert atmosphere such asin the presence of `a solvent havin-g a high vapor pressure, a dry inertgas such as nitrogen, etc.

Although the reaction may -be carried out over a broad temperaturerange, the reaction in general is carried out from about the meltingpoint of the wax up to below its decomposition temperature. In practice,the reaction is carried out at a temperature above about 60, such as 60to 300, for example 100 to 275, but preferably 200 to 250. The time ofthe reaction will vary depending on other reaction conditions. Ingeneral, reaction time can vary from at least |tive minutes, such as 5to 600 minutes, for example 10-200 minutes, but preferably l5 to 120minutes.

When the alkali metal is mixed with wax, :a black precipitate is formed.This precipitate is removed by any suitable means, for example, bycentrifugation, filtration, solvent extraction, for example by usingliquid propane, adsorption on anfactive surface, etc. Removal of theprecipitate yields a wax which isl not only light in color but alsocontains less sulfur, nitrogen, combined oxygen, trace metals, aromaticsand other undesirable' materials.

Although the nature of the reaction .taking place during the process isnot understood, it is believed, among other things, that` the reactiontakesplace between the alkali metal and petroleum resins, asphaltenes,aromatics, sulfur and nitrogen containing materials and otherundesirable impurities present in the wax.

The alkali metal is employed in amounts suflicient to decolorize thewax, for example, in at least about 0.005% by weight .of alkali metalbased on the wax or crude wax charge, such as 0.01 to 10.0% or higher,for example 0.01 to 2.0%, but preferably 0.02 to 1.0%.

ALKALI METAL-ETHER TREATMENT Although the alkali metal treatment can berun without a solvent, it can also be carried out in the presence ofvarious inert solvents, for example, non-reactive hydrocarbons in whichthe wax is soluble. However, there is This liquid state can be achievedA a specific class of solvents which facilitates Ireaction so thatreaction takes place within a shorter time under milder conditions. Theaction of the ether is specic, but it is not known whether the action iscatalytic, whether the ether itself takes part inthe reaction in somemanner, or whether there are some solubility or other factors involved.

In practice, the temperature at which the Ireaction is run will dependon such factors as the solubility of the ether in the wax at theparticular temperature, the boiling point of the ether, etc. Becausemany ethers are low boiling and do not dissolve wax at low temperatures,it is often desirable to run the reaction under super-atmosphericpressure so as to heat the reaction mixture to a temperature at whichthe ether dissolves the wax. Whenever the ether boils at a satisfactoryrange for example 75-200 C., it is convenient to run the reaction at thelreliux temperature ofthe ether.

Suitable ethers include (l) aliphatic ethers containing a CHaO-group and(2) cyclic aliphatic ethers, in each case the number of oxygen atoms andthe number of carbon atoms being in a ratio of not less than 1:4. In thephrase oxygen-carbon ratio of not less than 1:4 the ratio of 1:4 refersto the ratio of the number of oxygen atoms to the number of carbon atomspresent in the ether. Examples of these ethers include the following:

14 where R is hydrogen or a lower alkyl group which Rs may be the sameor different provided that the ratio of oxygen to carbon is not lessthan 1:4, for example, the dimethyl ether of ethylene glycol, methylethyl ether of ethylene glycol, methyl propyl ether of ethylene glycol,corresponding propylene glycol ethers, trimethylene glycol lethers,etc.; polyethers of the general formula whe-re n and x are integers, forexample 1 4v and at least one of the CnH2n+1 groups is methyl, providedthe ratio of oxygen to carbon is not less than 1:4, for example, thetrimethyl ether, the dimethyl ethyl ether, the methyl diethyl ether,dimethyl isopropyl ether of glycerol, etc.

Other examples include the ethers of pentaerythritol, etc., having aCHaO-group and a O/C ratio of not less than 1:4.

Suitable cyclic ethers include, for example, tetrahydrofuran, dioxolane,methyl glycerol formal, dioxane, etc.

Other suitable ethers include those of the general formula where n=1-4and x=24 with the proviso that the oxygen to carbon ratio is not lessthan 1:4, for example the ethers of -polyethylene glycols such asdimethyl ethylene glycol, dimethyl diethylene glycol, dimethyldipropylene glycol, ethers of mixed alkylene glycol, for example Otherethers not within the scope of the above, such as diethyl ether,diisopropyl ether, methyl phenyl ether, methyl benzyl ether, etc. may bereactive with certain more active alkali metals. In general, the easewith which the reaction starts decreases with increasing weight of thealkyl ether group. With methyl ethers of the higher alkyls, it may benecessary to add a small amount of an effective ether to start thereaction, as the reaction appears to be definitely autocatalytic whenonce started.

Within the restrictions above given as to the limitations of the etherseffecting the reaction, these ethers must furthermore not be split bythe alkali metal under the conditions used.v This does not mean that theethers may not Ireact in some way in some reversible reaction with thealkali metal since indications are that the ethers in effecting thereactions may, to some extent, take part in the reaction, but the ethermust not be broken up or form irreversible reaction products. Thus, forexample, ethyl- 'ene oxide may be considered a cyclic ether fallingwithin the limitations given for oxygen-carbon ratio; however, it reactswith the alkali metal and hence cannot satisfactorily perform thefunction required. There may be Very vslow ether cleavage with some goodsolvents, but at a H role in causing the reactions to proceed.

The weight ratio of ether to wax can vary wide, for example, from atleast about 1:25, or less, such as 1:25 to 25:1 or more, for example 1:4to 4:1, but preferably 1:2 to 1:1.

However, the optimum amount present depends, among other factors, on theparticular ether employed, the solubility of wax in the ether, etc.

To minimize solubility of the precipitate in the wax, ether ispreferably removed prior to removal of the precipitate. This isconveniently done by distilling ether from the wax.

CARB ONATION After alkali metal or ether-alkali metal treatment, thereaction mixture can be carbonated by adding carbon dioxide thereto lat,any convenient temperature. Since the carbonation reaction does notappear to be temperature dependent but operative over a wide temperaturerange, all that is required is that the wax be in a liquid state. Thus,provided this state is maintained, carbon dioxide can be added in a`gaseous state or added as solid Dry Ice. Super-atmospheric pressure maybe employed to prevent carbon dioxide escape. If desired, the alkali'metal treated wax can be added to an inert liquid medium containingcarbon dioxide such as ethers, non-reactive hydrocarbons, etc.

In practice,-the reaction is carried out at a temperature of at least 30C. such as 430" to 200 C., for' example 60 to 140 C., but preferably 80to 100 C. The reaction is substantially instantaneous. In practice, werun the reaction for a period of at least tive minute-s, such as 5 tomin., for example 10 to 90 min., but preferably 15 to 60 min.

After carbonation of these waxes, the product is treated by any suitablemeans such las ltnation, centrifugation, extraction, adsorption, etc.,to remove insoluble materials.

In general, at least one gram-mol of carbon dioxide is added for eachgrani-atom of alkali metal added.

In practice excesses of carbon dioxide are employed by bubbling CO2 inthe reaction mixture or -adding solid Dry Ice thereto. Where ether isemployed, it is preferred to have the ether present during carbonation.Ether removal is effected after carbonation and prior to precipitateremoval.

OXYGENATION The alkali metal treated wax, or the ether-alkali metaltreated Wax, can also be treated with oxygen, yan oxygencontaining gassuch as air, ozone, etc. The process is carried out in the mannerdescribed for the carbonation process and under the same reactionconditions. Subsequent to oxygen addition any precipitate present isseparated from the wax.

In genenal, at least one gnam-mole of oxygen i-s added per gram-atom ofalkali metal added. In practice, excesses of oxygen are employed bybubbling oxygen or an oxygen-containing gas, such as air, into thereaction mixtures.

As previously mentioned herein, the wax ltrate resulting from ltrationof the alkali metal treated wax is tested for condensed ringaromaticity. If it tests positively -for condensed ring aromaticity,additional alkali metal, preferably with ether, is added prior tocarbonation or oxygenation. -Wher-e ether is employed, it is preferredto `have ether present during oxygenation. Ether removal is effectedafter oxygenation -and pirior to precipitate removal.

microwax after deoiling (wax type 15) isremployed un` der the conditionsstated in Table II, Example 2.

Example 3 Petrolatum (100 g.) (wax No. 14) is treated with a lump ofsodium (1 g.) in the manner of Example l.

The precipitate in Part I is separated from the wax by means of a heatedcentrifuge. The conditions ernployed are stated in Table II, Example 4.

Since the following examples are carried out in a similar manner to savespace, they will be presentedin tabular form. The type of wax employedis identified by the numbers shown, which refer to the waxes of Table I.The wax products are blown with CO2 and O2 by passingthese gases intothe reaction mixture for ten minutes at the rate of `about 1 g./min.

Where the pro-ducts of Part I are further hydrogenated with a compoundcontaining an active hydrogen (see Table VI), some of unfiltered Part Iproduct is preserved for such hydrogenation. l

TABLE II.-ALKALI METAL TREATMENT Y.

Alkali Metal Part I Part II Part III Wax Time in Alkali Metal Plus Ex,Type Weight Temp. Hrs. Carbonylation Name Percent Method of Separation(Unfiltered) Metal in Wax Temp. Temp.

8 1. 0 250 1 Filtration 100 100 15 1. 0 200 1 d0 100 100 S 1. 0 250 1Propane Extraction 150 125 14 1. 0 250 1 Centrifugation. 100 100 15 1. 0175 3 Filtration 100 150 8 2.0 200 3 do 100 100 8 5. 0 150 5Centrifugation- 100 100 14 2.0 190 3 do 150 125 20 0. 5 200 2Filtration. 150 150 21 0.1 200 3 do 150 100 21 0. 1 200 2 PropaneExtraction 80 100 8 0. 05 200 1 Filtration 80 100 27 0.05 200 0.5 do 15080 27 1. 0 240 l centrifugation. 100 80 8 0.02 220 1 do 150 75 8 0. 05200 1 Filtration. 75 100 8 0.1 200 1 do 100 100 15 0. 1 200 1 do 100 10015 0.05 200 0.5 do 150 150 14 0. 05 240 0. 5 Propane Extraction 125 12520 0. 05 200 0. 5 Filtration 150 100 27 0.05 200 0.5 do 200 150 TABLE IIEXAMPLES Example 1 Employing an inert atmosphere of dry nitrogen crudetank bottom derived microcrys-talline wax after deoiling (100 g.) (waxtype 8) and a lump of sodium (1 g.) are added to' a dispersator. Thetemperature is raised to 250 C. while the dispersator is run at highspeed for one hour to convert sodium to `a tine dispersion. Thetemperature is maintained at 250 for about one hour. The product is thendivided into three equal parts. In Part I the precipitate formed is thenseparated by iltration to produce a White wax which is essentially freeof sulfur, nitrogen and oxygen. Part II (uniiltered) is blown with anexcess of CO2 at 100 C. for ten minutes. The precipitate formed is thenremoved by filtration. Part III (unltered) is blown with an excess of O2at 100 C. for ten minutes and the precipitate is separated byfiltration.

Example 2 TABLE III EXAMPLES ethane, and 0.1 g. of sodium are charged toa liask equipped with a stirrer and condenser. The reaction mixture isblanketed with dry nitrogen, heated to reux and thus maintined `for onehour. The product is then divided into three equal parts. In Part I,after removal of the ether by distillation, the precipitate formed isseparated by filtration. Part II is blown with excess CO2 just above themelting point of the wax product for ten minutes. Then after removal ofthe remaining ether by distillation, the precipitate formed is separatedfrom the wax by filtration. Part III is blown with an excess of O2 justabove the melting point of the wax product for ten minutes, theremaining ether is removed by distillation and the precipitate formed isseparated by filtration.

Example 2 The process of Example 1 is repeated except thattetrahydrofuran is employed in the amounts stated in Table Ill.

' 9 Example 3 The process of Example l is repeated except that typeTable II), some of unfiltered Part I is preserved for suchhydrogenation.

TABLE IIL-ETHER-ALKALI METAL TREATMENT Alkali Metal Ether Part I WaxTime, Ex. Type Weight Weight Hours Separation of Part II Part III Namepercent Num- Ratio Precipitate Metal ber Ether in Wax to Wax 1 8 0. 1 11 1 Filtration All examples All examples are treated are treated withCO2. with O2. 8 0. 1 2 0. 5 1 0. 05 4 1 2 15 0. 1 3 1 1 8 0. 1 1 1 1 140.2 1 0.5 1 ..do 8 0. 1 2 0. 25 0. 5 Centrifugation 8 0. 5 2 0. 5 0. 5Propane Extraction. 1. 0 4 0. 25 1 Filtration 21 2.0 1 0.5 1v do 27 0.051 0.5 1 do 27 0. 1 2 0. 25 1 Centrifugation. 8 0. 01 2 0. 75 0. 5Filtration 15 0.01 2 1 1 do 15 wax and the dimethyl ether ofdlethyleneglycol are HYDROGENATION employed in the amounts stated inTable IH.

Example 4 Type 15 crude wax (100 g.), 100 g. of methyl isopropyl etherand 0.1 g. of sodium are charged to a rocker autoclave. The reactionmixture is heated to 90-100 C. and thus maintained for one hour underambient pressure. This product is divided in three equal parts andtreated in the manner of Example 1. The wax is raised to its meltingpoint at which time the respective gases are added under pressure.Excess ether is removed during filtration.

Since the following examples are carried out in a similar manner, tosave space, they will be presented in tabular form. The type of waxemployed is identified by the number shown, which refers to the waxes ofTable I.

All reactions are run at reux, employing one of the following ethers,except where methyl isopropyl ether is employed where the reaction isrun at 90-100 C. in a rocker autoclave at ambient pressure. CO2 and O2are added just above the melting point of the Waxproducts.

(1) 1,2-dimethoxyethane (B.P. 85.2 C.)

(2) Tetrahydrofuran (B.P. 66 C.)

(3) Methyl isopropylether (B.P. 32 C.)

(4) Dimethyl ether of diethylene glycol (B.P. l62.0 C.)

These ethers are identiiied by number in Table III. CO2 and O2 are addedfor ten |minutes at the rate of about 1 g./min. at just above thetemperature at which the wax products melt.

Where the products of Part I are further hydrogenated with a compoundcontaining an active hydrogen (see We have also found that the alkalimetal treated wax (or ether-alkali metal treated wax) can be furthertreated Ito remove additional trace amounts of undesirable impurities byreacting the Wax with either (1) hydrogen or (2) a compound containingan active hydrogen atom.

Thus, the term, hydrogenation includes reduction by means of either (1)0r (2).

(l) Hydrogenation with hydrogen 0f the alkali metal treatedwax.-Hydrogenation is effected by contacting the alkali metal treatedwax in a liquid form Withhydrogen at elevated temperatures andpressures, the duration of the treatment and the temperature beingregulated so that the wax suffers substantially no cracking or splittinginto low molecular liquid products.

, Any of the conventional systems of hydrogenating hydroearbons can beemployed. For example, temperatures in excess of about C. such as 60 to300, for example '80 to 250 but preferably 150 to 200; at pressures inexcess of l0 p.s.i. such as 10 to 500 p.s.i. for example 50 to 450p.s.i. but preferably 200 to 400 p.s.i. The duration of the treatmentwill vary depending on conditions such as temperature, pressure,catalyst, etc. However, in general the duration of treatment isgenerally in excess of 1 min., such as 5 min. to 24 hours, forexample5.0 to min., but preferably 15 to 60 min. The duration of the treatmentis generally shortened as the temperature is increased in order to avoidsubstantial cracking of the wax. Of course, it should be realized thatthe above conditions are generally stated and can be varied since theconditions are interdependent.

The following are examples of catalyst systems that can be employed inthe process:

TABLE IV Catalyst Manufacturer 72% Ni on kieselguhr 0.5%

5% Pt on car on Harshaw Chemical Company. Bohen & Company. Universal OilProducts. Engelhard Industries.

on alumina 10% Ni as nickel oxide on alumina 82% CuO, 17% CMO; 41% CuO,44% CrgOs, 11% BaO Raney Nickel Copper-chromium oxide.

5% rhodium on alumina 5% ruthenium on alumina... 5% rhodium on carbon 5%ruthenium on earbon. Pd on strontium carbonate 5% Pd on carbon AdamsCatalyst (PtOg) Hariaw Chemical Company.

Do. W. R. Grace. Pregziged according to JACS 72, 2626 Prepared accordingto JACS 44, 1397 11 12 The above catalysts are merely exemplary of those175-200 p.s.i. for one-half hour. The product is then that can beemployed. filtered.

Hydrogenation catalysts and processes `of hydrogena- Example 4 tion areso well known to the art that further examples are unnecessary. Thepreferred'hydrogenation catalysts which are employed are those capableof hyldrogenating aromatic compounds. Examples of 'such catalysts can befound in chapter 4 of Catalysis, volume V, Emmett, Reinhold PublishingCorporation (1957) and elsewhere.

The process of hydrogenation can be conducted on a batch or continuousbasis using any type of reaction or series of reactions known to theart.

The catalysts may be employed in the form of powder intimately mixedwith wax prior to treatment with hydrogen under pressure and at the endof this treatment they are separated from the wax, for example, byfiltering, or centrifuging the product and are available for therefining The product of Table II, Ex. 3, Part I, and 1% by Weight ofruthenium on alumina are placed in a rocker autoclave and treated withhydrogen at 200-210? C. and 350-400 p.s.i. for one-half hour. Theproduct is then filtered.

Other products also hydrogenated are presented in the following table.The designation employed for the product hydrogenated refers to thetable, example, and part. Thus II 1, Part I refers to Table' II, Example1, Part I. The catalyst number refers to those catalysts of Table IV.Thus, catalyst 1 refers to 72% Ni on kieselguhr. In all cases theproduct hydrogenated whether in Part I, II or III is filtered prior tohydrogenation.

TABLE V.-HYDROGENATION WITH H2 Catalyst Time Temp., Pressure, Ex.Product Hydrogenated (Hr.) C. p.s.i.

No. Weight percent II 1 Part I 1 1 l 200-210 450-500 II l Part II.. 8 l1 150-160 250-300 II 1 Part III 12 l 0.5 90-100 175-200 II 3 Part I...11 1 O. 5 200-210 S50-400 II 5 Part II.. 15 1 1 60-70 175-200 II 9 PartII.. 4 1 1 100-110 225-250 II 13 Part. I 1 l. 5 0.75 150-155 175-200 II19 Part; IIL.-- 12 1 1 170-175 20G-225 II2 Part I 11 1 1 20D-215 21o-240III 1 Part. I.. 15 0.5 1. 5 140-150 275-300 III-1 Iart II 4 0.5 1. 5120-125 30G-325 III 4 Part II 1 0. 05 2 145-155 225-250 III 6 Part I..l2 0.5 1. 5 190-200 275-300 III S Part II. 1 0.05 1. 75 200-215 375-400III l0 Part I 4 0.5 l. 5 190-200 150-175 III 12 Iart III..- 11 1 1140-150 175-20() III 13 Part I .1 1 1 170-175 175-200 of additional wax.The catalysts may, however, be disposed separately, in a coarse form inthe reaction chamber the molten wax being then passed over them with acounter-l or equidirectional flow of hydrogen. For example, a mixture ofmelted wax and hydrogen gas is fed to the hydrogenation reactioncontaining the catalyst.

This mixture is preferably preheated to the reaction tem- TABLE VEXAMPLES l Example 1 The filtered product of Table II, Ex. 1,'Part I, isplaced on rocker autoclave and 1% by weight of nickel catalyst (onkieselguhr).is added thereto. The system is swept withhydrogen and thenpressurized. The temperature is then raised to G-210 C. for 1 hour at anoperating pressure of 450-500 p.s.i. The product is then filtered.

Example 2 The filtered product of Table II, Ex. l, Part II, and 1% byweight of Raney nickel are charged to arocker autoclave. The system isswept with hydrogen, heated to 15G-160 C. at Z50-300 p.s.i. and thusmaintained for one hour. The product is then centrifuged.

Example 3 The filtered product of Table II, Ex. l, Part III, and 1% byweight of rhodium on carbon are placed in a rocker autoclave and treatedwith hydrogen at 90-100 C. and

gram-mol No. of active hydrogen on molecule of the active hydrogencompound is added for each gramatom of alkali metal.

In practice, however, excesses of active hydrogen compounds are employedfor example 5-10% or more of the active hydrogen compound based onweight of wax.

As previously noted, after filtration of the alkali metaltreated wax itis advisable to examine the wax filtrate for condensed ring aromaticity.If the wax filtrate tests posivitely for condensed ring aromaticity, oneadds additional alkali metal, preferably with ether, and then proceedsto hydrogenate with an active hydrogen compound in the manner of thisinvention.

By a compound containing an active hydrogen We mean a compound having anactive hydrogen which is capable of reacting with an alkali metal or analkali metal organic compound, for example, the reaction product ofsodium and a condensed ring aromatic compound.

The addition of compounds containing an active hydrogen to alkali metaltreated wax results in a wax containing less impurities. Examples ofsuch compounds comprise alcohols, for example methanol, ethanol,propanol, etc., acids, for example formic, acetic, propionic, etc. acidsand the like.

In carrying out the process, these compounds are added to the alkalimetal treated wax so as to react with the components present therein ata temperature sufficient to cause reaction, the duration of thetreatment and the temperature being regulated so that the wax sufferssubstantially no cracking or splitting into low molecular liquidproducts such as occurs at temperatures in excess of 300 C., for example60 to 200 C., but preferably 60 to 150 C.; for a period of at least 1.0min. such as 1.0 to 120 min., for example 5 to 901mm., but preferably 10to 30 min. Whenever convenient, it is preferred to run the reaction atrefiux. The conditions of the treatment will vary depending on thecompound employed. The duration of the treatment is generally shortenedas the temperature is increased in order to avoid substantial crackingyof the wax. Where the compound containing an active hydrogen is lowboiling, superatmospheric pressure can be employed. Excess amounts ofthe compound after reaction can then be removed under reduced pressure.

TABLE VI EXAMPLES Example 1 The .product of Table II, Ex. l, Part I(unfiltered), and by Weight of methanol are heated at reflux for -20minutes. T-he product is then filtered. Excess methanol is distilledfrom the product.

Example 4 Exam ple 6 The product of Table II, Ex. 13, Part I(unfiltered), and 10% by weight o f acetic acid are heated at reflux forl5 minutes. The product is then filtered. Excess acetic acid isdistilled from the product.

The following examples are carried out in a similar manner. Ten percent(by weight based on wax) of the active hydrogen compounds is employed inall examples .and the reaction mixture heated to reflux. Where ether isemployed in the prior step, the alkali metal ether treated product isnot vfreed from ether until after treatment with a compound containingan active hydrogen and prior to filtration.

TABLE Vlr-HYDROGENATION WITH COM- POUNDS HAVING ACTIVE HYDROGENS FURTHERTREATMENT OE WAX FILTRATE III PRODUCT The following examples arepresented yto illus-trate fur- .ther treatment of the product of alkalimetal treated wax,

after precipitate removal (i.e. wax filtrate III).

Example A Example A1 .-Wax filtrate III obtained from Table II, Example1, Part I, is found to contain condensed ring 14E aromaticity.Thereupon, 0.5% sodium and 1,2-dimethoxyethane is added in an ether towax rat-io of 0.25 and heated to reflux for one hour. The resultingprod-uct is divided into Part I, Part II, and Part II-I.

Example A2.Part I is blown with CO for ten minutes, ether is distilledfrom the wax, and the precipitate formed removed by filtration. Theproduct has no measurable condensed ring aromaticity as measured -byultra-violet -absorbence and fluorescence. The product is AI wax.

Example A3.-Part II is blown with O2 for ten minutes, ether is distilledfrom the wax, .and the precipitate formed removed `by filtration. Theproduct contains measurable condensed ring aromaticity as determined byultra-violet `absorbence and fluorescence. The product is a DI wax.

Example A4.-This product is ythen hydrogenated with hydrogen for onehour at 20G-210 C. and 450-500 p.s.i. in the presence of 1% Ni (72%) onkieselguhr. After treatment no measurable condensed ring aromaticity isobserved. The product is a DII wax.

Example xii-Part III is heated with 10% by Weight of ethanol at refluxfor l5 min., excess ether and alcohol are distilled from the wax, andthe precipitate then removed by filtration. r[The product formed has nomeasurable condensed -ring aromaticity. The product is an EI wax.

xample B Wax lfiltrate III from Table II, Ex. 5, Part I, treated withNa-K 50:50 alloy is found to contain very low condensed ring aromaticitywhen tested by ultra-violet absorbence.

Similar treatment can be effected with other Wax filtrates III productsformed in accordance with this invention, for example those of Table II,Part I.

The waxes refined by the processes of this invention either by alkalimetal alone, or by alkali metal ether, or either of these processes incombination with hydrogenation, oxygenation, carbonylation, oroxygenation followed by hydrogenation, or carbonyla-tion followed byhydrogenation, carbonylation followed by hydrogenation, etc., arecharacterized by the removal of or the reduction in color andcolor-forming bodies, aromatic content, sulfur, nitrogen, rcom-binedoxygen, trace metals and other undesirable materia-ls.

Besides producing a wax of excellent physical proper- -ties such as inregard to melting point, plasticity, penetration, etc., an additionaladvantage of these processes over other refining processes is that theypresent a facile method of removing color and color-forming bodies andother impurities which are either too difficult or Itoo expensive toremove by other methods. They .are particularly effective in removingcondensed ring aromaticity present in the wax. Convenient and acceptablemethods which we have employed in determining .the amount of condensedring aromaticity in waxes comprises subjecting wax to an ultra-violetand/ or fluorescent examination. Based on such examination the condensedring aromaticity of alkali metal treated waxes is less than thecondensed ring aromaticity of the wax prior to treatment. However, thecondensed ring aromaticity of wax subjected to alkali metal alone(although substantially reduced from the wax prior to treatment) is notas much reduced as when the wax is treated with alkali metal incombination with oxygenation, carbonation, or hydrogenation, orcombinations thereof.

A-romaticity, especially in terms of condensed ring aromaticity, can beeffectively determined by both ultraviolet absorption spectra andfiuorescence spectra. The spectra obtained allows qualitative andquantitative determination to be made on the wax or any componentremoved 4from the wax, by such means as chromatography. Condensed ringaromatics exhibit characteristic spectra of both types which arecharacteristic of their structure, so that matching with spectra ofknown compounds is practical. This type of analysis lends itself readilyto the determination of extremely low concentrations (in the order often parts per billion) as has been illustrated in the literature.

In general, ultraviolet absorption spectra are obtained by the followingprocedure:

A 1-3% solution of the wax is prepared using spectroscopically pureiso-octane. The concentration may be adjusted in some cases if too largeor too small of an amount of absorbing Amaterial is present in the wax.Quartz cells are used and the wax solution is run against the solventused. Any ultravolet spectrophotometer may be used if the spectrabetween 260-330 millimicrons can be scannedusing a hydrogen lamp as thelight source. Any components separated from the wax by chromatographicprocedures, distillation, extraction, etc., can be analyzed using thissame general procedure. The procedure published by Lizinsky, W.,Analytical Chemistry, 32, 684-687 (1960) is illustrative.

In general, fluorescent spectra are obtained by the following procedure:

Solid samples of wax either in quartz cells or as solid plates of waxare employed. Any uorometer or ultraviolet spectrophotometer withuorometer attachment, such as available for the Beckman DK-l or DUinstruments, is suitable. The procedure as outlined by Eichkotl, H. I.,and Tischack, G., Erdol and Kohle 705-708 (1958) is generally used.Also, as with the ultraviolet spectra, any components that can beisolated by chromatographic procedures, distillation, etc., can be eX-amined using a solution with a solvent, such as spectroscopically pureisooctane or ethanol.

In both cases, i.e., with ultraviolet and uorescent examination,qualitative andquantitative determinations are made by comparing thespectra of the unknown wax with that known compounds or by comparing thespectra of the unknown Wax with the spectra of components separated fromthe wax.

Although various embodiments of our invention have been describedherein, many variations thereof can be practiced without departing fromthe spirit of the invention.

For example, any of the procedures described herein in the specificationand claims can be practiced in conjunction With conventional waxrefining techniques such as treatment with absorbent materials such asbauxite, clay, alumina, charcoal, silica gel and the like. Suchtreatment can be carried out as'a step in the process or subsequent tothe completion of the process.

In addition to the alkali metals described herein, certain alkali metalcompounds which react in the manner of alkali metals can also beemployed, for example, alkali metal alkyls such as ethyl sodium, alkalimetal-alkali earth alloys for example the sodium-calcium alloys, alkalimetalammonia combinations, alkali metal-amine combinations, sodamide,etc.

In all cases except carbonated or oxygenated wax, the term hydrogenatingas employed herein refers to treating the wax with either hydrogen or acompound containing an active hydrogen. With carbonated or oxygenatedwax, the term hydrogenation refers only to hy- Y drogenation withhydrogen.

The term, hydrocarbon wax as employed herein refers the wax itself orwax-containing composition such as intermediates in the preparation ofhydrocarbon waxes.

These waxes are particularly useful in food applications, such as foodWrappers, food cartons, etc.

Having thus described our invention, what we claim as new and desire toobtain by Letters Patent is:

1. A process of refining a hydrocarbon wax which includes treating saidwax rst with an alkali metal alone vand then hydrogenating said wax. i i

2. A process of relining a hydrocarbon Wax which includes treating saidwax with an alkali metal alone in the presence of a stable etherselected from the group consisting of (1) an aliphatic ether containinga CH3O-group and (2) av cyclic aliphatic ether, a number of oxygen atomsand the number of carbon atoms in said stable ether being in a ratio ofnot less than l1:4, and then hydrogenating said wax.

3. A process of refining a hydrocarbon wax which includes treating saidwax first with an alkali metal alone, separating the wax from theprecipitate formed, then hydrogenating said wax, and then separating thewax from the precipitate formed.

4. A process of refining a hydrocarbon wax which in,- cludes treatingsaid wax with an alkali metal alone in the presence of a stable etherselected from the group consisting of (1) an aliphatic ether containinga CHgO- group and (2) a cyclic aliphatic ether, the number of oxygenatoms and the number of carbon atoms in said stable ether being in aratio of not less than 1:4, removing said ether, separating the wax fromthe precipitate formed, hydrogenating said wax and then separating thewax from the precipitate formed.

5. A process of rening a hydrocarbon wax, which has been treated with analkali metal alone in the absence of ether and then separated from theprecipitate formed, which inclu-des hydrogenation of said treated andseparated wax with hydrogen.

6. A process of rening a hydrocarbon wax, which has been treated withalkali metal alone in the absence of ether and then separated from the,precipitate formed, which includes further treatment of said treatedand separated waX with alkali metal in the presence of an ether selectedfrom the group consisting of (l) an aliphatic ether having a CHaO-groupand (2) a cyclic aliphatic ether, the number of oxygen atoms and thenumber of carbon atoms in the stable ether being in the ratio of notless than 1:4, and then hydrogenating the product with a compound havingan active hydrogen.

References Cited by the Examiner UNITED STATES PATENTS 1,983,220 12/1934 Fields 208-284 2,042,557 6/ 1936 Sparks 208-294 2,385,431 9/1945Vose 208-284 2,586,198 2/ 1952 Backlund et al. 208-27 2,789,134 4/195-7Nelson et al 208-284 2,908,702 10/1959 Haines et al. 208-20 2,915,44812/ 1959 Annable et al 208-27 2,956,001 10/ 1960 Spars et al. 208-273,056,773 10/ 1962 Joo et al. 208-294 FOREIGN PATENTS 247,357 5/1912Germany.

OTHER lnnnnltusrtcl-:s

Dietz et al.: Ind. & Eng. Chem., vol. 44, No. 8, August 1952, pages1818, and 1819.

DELBERT E. GANTZ, Primary Examiner.

ALPHONSO D. SULLIVAN, Examiner.

H. LEVINE, Assistant Examiner.

1. A PROCESS OF REFINING A HYDOCARBON WAX WHICH INCLUDES TREATING SAIDWAX FIRST WITH AN ALKALI METAL ALONE AND THEN HYDROGENATING SAID WAX.